The present invention can be applied to a wireless communication system with a downlink frame structure including an FCH. Such a wireless communication system may include an Institute of Electrical and Electronics Engineers (IEEE) 802.16e-based wireless communication system.
In the present time, the Wibro (portable Internet standard in Korea) configures an IEEE 802.16e-based system in order to provide a high speed data service to users on the move, adopts an OFDMA as a multiple access scheme so that a plurality of users can simultaneously use an Internet service, and adopts Time Division Duplexing (hereinafter, referred to as TDD) as a duplexing scheme, the TDD distinguishing a downlink from an uplink based on time.
FIG. 1 is an exemplary diagram illustrating the frame structure of an uplink and a downlink in a TDD system. Downlink transmission from a Radio Access Station (hereinafter, referred to as RAS) to a Portable Subscriber Station (hereinafter, referred to as PSS) is implemented in a sequence of a preamble, an FCH, a Down Link MAP (DL_MAP), an Up Link MAP (UL_MAP) and a DL burst. Uplink transmission from a PSS to an RAS starts from control symbol transmission, and a Tx/Rx Transition Gap (TTG) for distinguishing uplink transmission time from downlink transmission time is inserted between a downlink and an uplink in the middle of a frame.
Generally, downlink signal in a wireless communication system is transmitted to the receiver of a PSS after having passed through an encoding process for error correction of the downlink signal and an interleaving process for burst error prevention in the transmitter of an RAS.
Then, the downlink signal transmitted from the transmitter of the RAS is received in the receiver of the PSS, and are subjected to a deinterleaving process for restoring signal in their original order by a deinterleaver. The deinterleaved signal is decoded by a Viterbi decoder, so that a code symbol is removed and the original signals are restored.
A signal directly next to a preamble in a downlink frame includes an FCH for transmitting frame configuration information of 24 bits, i.e. a Downlink Frame Prefix DL_Frame_Prefix. The DL_Frame_Prefix transmitted through the FCH corresponds to data early transmitted in each frame, and includes configuration information about a corresponding frame.
Since the DL_Frame_Prefix transmitted through the FCH is arranged in the front portion of the frame and includes important information about a corresponding frame, it is utilized as very important information in later reception processes for receiving a series of data including an entire frame. Accordingly, the DL_Frame_Prefix requires superior reception performance for various channel environments as compared to other parts of transmission data.
However, a conventional signal transmission/reception scheme has not provided a separate reception performance improvement scheme for the DL_Frame_Prefix information transmitted through the FCH. Therefore, when the DL_Frame_Prefix information is not normally received depending on transmission/reception channel environments, the entire reception performance of a system may deteriorate.